Well, let's think here. 10w-60 is a thicker oil which has a greater density. So my thinking is that the density of the oil would make it more difficult to lose heat. Since heat is just energy then you would have to lose twice as much heat since you have twice as many molecules (lets just say that for this example). But in fact I wouldn't worry about it. Because to raise the temperature further, it would take much more energy.

I wouldn't be surprised if it runs hot since it's harder to cool, but I betcha it will not get much hotter... Also, I bet it takes more time to heat the oil than the 5w-30. I also don't think it means more friction.